Formatting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175931 91177308-0d34-0410-b5e6-96231b3b80d8
Add a TODO and explain when we can get rid of the isMain field.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175932 91177308-0d34-0410-b5e6-96231b3b80d8
Add a field to the compile unit of where we plan on splitting out
the debug info for -gsplit-dwarf so we can encode that location
in the skeleton cu.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175933 91177308-0d34-0410-b5e6-96231b3b80d8
Use getSplitDebugFilename when constructing the skeleton cu and
update testcase accordingly to give the correct name to the cu.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175934 91177308-0d34-0410-b5e6-96231b3b80d8